The hand-held radio industry is constantly challenged in the market place for high audio quality, low-cost products that provide good reception and coverage. Radios generally include a receiver having a low noise amplifier (LNA) where several signal channels are processed simultaneously. The communication signals received by the radio are generally amplified prior to demodulation for increasing the dynamic range of the signal and increasing reception quality. In general, conventional radios operate over a limited frequency range. Accordingly, narrow band LNAs focus on a narrow band frequency range used by the radio. Narrow-band LNAs can exhibit low noise figures, high gain, and good impedance matching at relatively low power. In practice, a narrow band LNA includes inductive elements that provide for low power narrowband amplification and the associated benefits by exploiting a quality factor of inductance-based matching networks.
In contrast, software definable radios are allowing radios to operate over greater frequency ranges. For example, instead of being limited to a narrowband frequency range, the radios are capable of supporting communication over broader frequency ranges. The communication signals over the wider frequency also need to be amplified in similar proportion in order to provide good reception an quality. That is, a wide-band amplifier should generally provide uniform amplification across a supported radio bandwidth. However, narrowband LNA's which are optimized for narrowband applications are not suitable for wide-band applications. It is not generally possible to simply extend the bandwidth. For example, a narrowband LNA is not practical for wide-band applications requiring more than one decade of bandwidth such as for cable TV networks (i.e., 50-900 MHz bandwidth) due to the complexity of the wide-band matching networks. In such cases, LNA solutions exploiting the wide-band nature of transistors and resistors are typically used. Wide-band amplifiers in deep-submicron CMOS are attractive in order to enable the realization of low-cost highly integrated systems. Nevertheless, wide-band amplifiers are typically designed in silicon bipolar or GaAs technologies. A need therefore exists for providing low noise, high gain, impedance matching, characteristics of a narrowband LNA in a wide-band CMOS LNA design.